Lithium ion cells have been widely used in a variety of industrial products such as notebook personal computers, video cameras, digital cameras, personal digital assistants (PDAs), mobile communication terminals, and electromotion instruments. The lithium ion cells have many varieties in size, a wide application and a large market demand. Further, the lithium ion cells can be applied in some rigor circumstances such as rather low temperature and rarefied atmosphere for polar science research and climbing adventure. The lithium ion cells also sever as energy drivers with high power discharge.
Generally, there is a serious demand for sealability of such a specific cell applied in serious conductions. In current, two types of detection devices are available for detecting the sealability of a lithium ion cell.
One typical detection device includes a detection bottle with liquid accommodated therein. A detecting pipe and an evacuating pipe penetrate through opening of the bottle. One open end of the detecting pipe is submerged in the liquid accommodated in the bottle. A needle penetrates through an injecting hole of the cell and is in communication with the cell at one end thereof via a sealing member. The other end of the needle is in communication with the detecting pipe through a gas pipe.
In detecting operation, air is evacuated from the detection bottle for several seconds. During evacuating process, it is observed whether bubbles continuously arise from the detecting pipe. If there are bubbles arising from the detecting pipe, it is determined that the detected lithium ion cell has a sealability problem. In reverse, the detected lithium ion cell has a good sealability.
However, this detection device has slow detection speed and insufficient precision. For example, it takes about five minutes to detect whether there is a slight leakage at joints among an upper cover, a lower cover and the cylinder body of a certain cylindrical energy cell under a vacuum pressure of about 0.05 MPa.
The other type of detection device includes a container containing a detecting liquid, a clamp, and a high-pressure gas connection device. The clamp is used to clip and position the measured lithium ion cell in the container. The two ends of the high-pressure gas connection device are respectively in communication with the injecting hole of the lithium ion cell and a high-pressure gas supply.
In detecting operation, the measured lithium ion cell is submerged in the detecting liquid within the container, and then the cell inside is filled with high-pressure gas for several seconds. In the meantime, it is observed whether bubbles arise from the detecting liquid within the container. If there are bubbles arising from the detecting liquid, it is determined that the detected lithium ion cell has a sealability problem. In reverse, the detected lithium ion cell has a good sealability.
The second device allows for a relatively higher detecting speed than the first device. Nevertheless, to maintain a dry inside the lithium ion cell and produce no influence on the sequential liquid filling process, the detecting liquid must be filled into the container after positioning the cell in the container. Further, after accomplishing detection operation, the detecting liquid must be discharged out of the container prior to taking out the cell from the container. Accordingly, the second device requires a complicated operation. Thus, it is desired to improve operation efficiency of the detection device.